It is shown both theoretically and experimentally that under inverted surface conditions the surface recombination current of a bipolar transistor has an exponential nonideality factor >2. The behavior of the surface recombination current follows closely that of the excess leakage current in stressed-self-aligned silicon bipolar transistors at forward bias.<>
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The fabrication and electrical characteristics of MOSFETs incorporating thin gate oxides deposited by a modified plasma-enhanced chemical-vapor-deposition (PECVD) process are reported. The gate oxide deposition and all subsequent steps were carried out at or below 400 degrees C. These results represent the first demonstration of near-thermal-gate oxide quality. MOSFETs fabricated using a low-tempe...
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Conventional IMPATT diodes are the highest-power microwave semiconductor devices, but they are difficult to couple light into, challenging to integrate into monolithic circuits, to incorporate a third terminal, or to series combine. The lateral IMPATT diode is proposed as a solution to these problems. This device is planar and features contact and drift regions that are all adjacent to the wafer s...
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The influence of time-dependent voltages on hot-carrier generation in MOSFETS is studied by transient device simulation. For transient times down to the nanosecond range, no transient effects on hot-carrier formation and injection are found. This result is confirmed experimentally by substrate current measurements under various dynamic voltage conditions down to rise/fall times of 3 ns. This resul...
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A technique to couple an optical fiber to a silicon p-n junction diode photodetector is described. Spin on glass is used to create an alignment sheath to receive the tapered end of an optical fiber, to stabilize the structure, and to eliminate the air gap between the fiber and the photodetector. By using an antireflective film, differential responsivity of 0.58 A/W at a wavelength of 810 nm has be...
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A selective deposition process is used to fill vias in VLSI multilevel interconnection. Ni film is chosen as the via-filling material because of its compatibility with the underlying Al film. The vias are filled with a thin Pd film first and a thick Ni film. The deposited Ni film is uniform and smooth in the via regions. This film is not attacked by the plasma etch used in subsequent Al patterning...
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Gas immersion laser doping (GILD) is used to fabricate the base and emitter regions of narrow-base n-p-n bipolar transistors. The GILD process is unique in that it allows simple fabrication of box-like impurity profiles which can be placed very accurately in the vertical dimension (+or-100 AA). Transistors with base widths ranging from 700 to 1200 AA and DC forward current gains greater than 50 ar...
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The collector-emitter offset voltages of InAlAs/InGaAs heterojunction bipolar transistors grown by molecular-beam epitaxy are discussed. Both the difference between emitter and collector areas and electrical asymmetry between emitter and collector junctions in these mesa-isolated transistors account for the offset voltages observed. Devices exhibited offset voltages in the range of 50-300 mV, depe...
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Gate-quality N-rich amorphous SiN/sub 1.6/:H films prepared by plasma-enhanced chemical vapor deposition (PECVD) at substrate temperatures of 250 and 400 degrees C are discussed. Films of different thicknesses t, ranging from 20 to 1100 nm, were obtained by varying the deposition time. The flat-band voltage shift was found to be proportional to t and t/sup 2/ before and after UV illumination, resp...
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The retrograde twin wells and buried p/sup +/ layer are fabricated by a single lithographic step using high-energy ion implantation. The retrograde n-well is self-aligned to the retrograde p-well regions. This simple process allows a scalable CMOS structure for the very tight n/sup +/-to-p/sup +/ spacing. It provides latch-up immunity at the 1.5- mu m n/sup +/-to-p/sup +/ spacing and good isolatio...
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